Abstract
The response of melanomas was assessed retrospectively from the clinical notes on 52 patients from 3 centers in UK. The response was very variable. A tentative isoeffect curve was fitted to the UK data which gave a good fit to data from a prospective study from Yale. Clinical data from the Melbourn Clinic on response and fraction size showed a similar response to that from the UK and the combined data showed that the response to fraction sizes of 400-800 rad was significantly better (P about 0.01) than to fraction sizes of 200-299 rad.